International quality specifications information

Information for international quality specifications in our free herbs and spices resources collection.

International quality specifications

Herbs and particularly spices have always been highly-priced commodities and vulnerable to adulteration. In consequence simple standards evolved early. As an example, in 1180 in the United Kingdom in the reign of Henry II, a ‘peppers’ guild was established in London to set and enforce standards for spices. In 1429 it was incorporated into the Grocers Company which is still in existence. This guild was granted a charter by Henry VI to manage the trade in spices. This organisation was given exclusive power to garble (e.g. cleanse and separate) spices. The term is still in use today, for example in classifying types of pepper such as Tellicherry Garbelled Extra Bold Black Pepper (TGEB).

Today the two major international standards are those set by the United States and those set by the European Union (EU). Standards relying on the same general parameters also exist in those countries responsible for growing herbs and spices, for example the Indian Spices Board and the Pepper Marketing Board. These standards are influenced by those set by the major importing countries.

There are various types of test which make up the range of international standards:

• Cleanliness. This is a measure of the amount of foreign and extraneous matter, for example insect contamination, excreta or foreign bodies. Measurement is by physical determination (using microscopic analysis (. 30)) of contamination within aliquots (samples) of the product.
• Ash level. This is a measure of the level of impurities in a product, obtained by burning off the organic matter and measuring the residue of ash. This measurement is carried out by incinerating the herb or spice at 550°C to constant weight. Characteristic maximum figures exist for most herbs and spices.
• Acid insoluble ash (AIA) (or sand content): This is a classic determination of the cleanliness of the herb or spice. The measure is usually made in conjunction with the ash content by boiling the ash in 2N HCl and incinerating the residue (again at 550°C) to a constant weight. Again maximum figures exist for most herbs and spices. Prosecutions have in the past been based on high acid insoluble ash (AIA) levels within Europe, which are seen as indicating an unacceptably dirty product.
• Volatile oil (V/O) determination. This measure helps to identify whether the herb or spice has been adulterated, perhaps by addition of foreign materials, low quality or spent amounts of the herb or spice in question. The herb or spice is boiled under reflux conditions with water where the oil separates on top of the water and can be read off in a volume proportional to the mass of the product under test. Minimum percentage levels of oil exist for most major herbs and spices.
• Moisture content. This measure of the amount of moisture is important since moisture content determines weight, and weight is used in pricing. With highly priced commodities traded on weight, a 1% moisture increase in the product as shipped can result in increased weight and increased profits for the original exporter. Maximum moisture contents are set for all herbs and spices, based on the maximum allowable amount of moisture for the product to remain stable. Moisture content is generally determined within the herb and spice industry using the Dean & Stark methodology. This involves re-fluxing a known weight of the herb or spice in petroleum spirit and measuring the water that condenses at the bottom of the reflux chamber from the known weight of herb or spice. Generally the level is 12% max.
• Water availability. In recent years moisture content has been related to the Aw or the water availability of the herb or spice. The level of 0.6 Aw is generally accepted as a figure at and below which mould or microbial growth cannot occur. However, this figure is increased in several herbs and spices without problem due to the preservative effect of the oils contained within the spices. Examples are cinnamon, oregano and cloves where the oils have very strong anti-microbial effects.
• Microbiological measures. There is a range of techniques available for counting the numbers of a pathogen in a sample.
• Pesticide levels. Pesticide levels are not seen as a major problem given the (low) average daily intakes of these products by consumers. As a result, in the EU limited legislation exists for herbs whilst, for spices, the EU has determined there is no risk and no legislation is planned. Legislation is in a state of flux in the USA and limits may be introduced. In the interim, Codex limits for the nearest equivalent commodity may be a useful guide. Pesticide levels are assessed by either gas chromatography (GC) or high performance liquid chromatography (HPLC), depending on the pesticide in question.
• Mycotoxin levels. Mycotoxins, specifically aflatoxin and ochratoxin A, have been of concern within the last few years in the industry. Legislation governing the aflatoxin content of capsicum species, piper species, nutmeg, ginger and turmeric will be enacted in 2001 within the European Union at 10ppb total, 5ppb B1. With the USA the limit is currently 20ppb. HPLC is likely to be the reference methodology employed for these determinations.
• Bulk density/bulk index. This is an important measure, particularly in filling retail containers of herbs and spices. The herb or spices must be sifted or ground to give a certain density so that retail units appear satisfactorily full and comply with the declared weight. Densities may be measured packed down, e.g. after tapping the product so that it assumes a minimum density, or untapped: as it falls into the container without compression. This measure is usually defined as grams/litre or mls/100g.
• Mesh/particle size. Many spices and herbs are ground to give easier dispersion in the final food product. This process also aids the dispersion of flavour. Particle size is generally specified and is carried out using standardised sieves. Aperture sizes give a particle size, the products being ground to pass a certain sieve, and coarse matter recycled through the mill until it finally passes through the sieve. Sieves are characterised in micron sizes and typical requirements will be a 95% pass on a specified size of sieve. The older method of measuring sieve (hole) sizes was that of mesh which related to the number of holes per inch. However, confusing differences exist between American and British mesh sizes. The mesh size (number of holes per inch) depends on the diameter of the wire making up the sieves and this differs between nations. Thus a 25 mesh US sieve is equivalent to a 30 mesh BS (UK) sieve and both are equivalent to a 500 micron aperture size. Tables are available giving the relationships between national sieve sizes and micron sizes.

There are a number of internationally-approved standards for testing procedures, established by the International Standards Organisation (ISO). These include the following ISO standards:

• Moisture - ISO 939
• Total Ash - ISO 928
• Acid Insoluble Ash - ISO 930
• Volatile Oil - ISO 6571

• American Spice Trade Association (ASTA)
• Quality tests
• Quality assurance systems
• Essential oils
• Essential oils adulteration problem
• Organic spices

• ISO list of plant spices
• The trade in spices
• Spice producing areas
• Spice flavours
• Herbs and spices functional role
• Quality specifications

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